Storage System for Two-dimensional Mixed Media Shadow Puppets with Plastic Film
The storage system was developed for a collection of shadow puppets (ca. 1930’s-1970’s) composed of mixed media including paper, cardboard, cloth, textile, hide, metal, and plastic films including cellulose nitrate. Puppets made with cellulose nitrate and other plastic films prompted the modification of a standard storage system. [Figure 1]
While cold, dark, and a low to moderate RH storage environment is considered the best environmental conditions for long-term preservation of off-gassing plastics, cold storage in this instance was not available. An alternative system was needed to address the complex storage issues that plastic films present, in particular off-gassing.
For the puppets constructed with plastic film, storage parameters included; passive airflow; use of non-reactive materials; ease of handling; limiting movement during transport; and keeping the collection together.
The key features of the storage design involved the modification of the top and bottom panels of the storage box to allow for airflow yet keeping dust deposits to a minimum, and the construction of volara-covered support-lifts to limit contact between reactive materials, especially the cellulose nitrate with paper buffered with calcium carbonate. Buffered paper in proximity to the off-gassing material is considered beneficial, but direct contact is not recommended. (Hatchfield). [Figure 2]
Debora D. Mayer
Helen G. Glaser Conservator
Weissman Preservation Center
Photo Credits: Debora D. Mayer
Every puppet in the collection was housed in an archival cardboard clamshell box of the same dimension (16 x 20 x 1 1/4”depth was used). [Figure 3] The interior of each box was fitted with a removable, archival cardboard lift for support and handling of the puppet. Bumper blocks of volara-covered ethafoam were placed strategically to limit movement of the objects within the box. [Figure 6] Because puppet segments, such as the head and limbs, were constructed with rivets to allow for movement in use, the large puppets could be swiveled into an arrangement to fit into a uniform size storage box.
For the puppets in the collection constructed with plastic films the storage boxes and support lifts were significantly modified. All but a 2” margin around the top and bottom panel was cut away to make a large opening to permit passive airflow and diffusion of off-gasses; the opening was covered with hollytex (stretched on a window mat) to prevent dust accumulation; spacer feet were attached to the exterior of the box bottom creating a space for air to flow between the boxes when stacked [Figure 4]; the support-lift below the puppet was covered with volara to provide both a barrier between the buffered paper board of the lift and box as well as a soft cushion for the potentially brittle film [Figure 5]; and corner blocks of ethafoam were positioned in the box corners to add structural support to the box for stacking.
Materials, Tools & Supplies
- E-Plus clamshell box. Die-cut. Paper furnish is buffered (3% calcium) lignin-free fiber and constructed of laminated plys of white paper/corrugation/grey-blue paper (Heritage board 1.7mm thickness). Shipped flat (Talas T14)
- Panel screen. Hollytex 3257 (non-woven polyester) or other similar material (Talas)
- Mat for panel: same board type as box construction, Heritage board (Talas)
- 3M 415 double-sided tape (Talas)
- Ethafoam (closed cell, non-cross-linked foam plank, 2 lb. density) (Conservation Resources)
- Volara 1/8” and ¼” thick sheets, Type 2A density (Talas)
- Acid free corrugated board (Talas)
- Jade 403 PVA adhesive (Talas)
- Dow 4M Methylcellulose (Hollinger Metal Edge, BMMC)
- 3M 3792-Q-LM, (Low melt) Jet melt adhesive (John G Shelley)
- Polygon LT Adhesive Applicator Gun
- Olfa knife or other knife
- With box unfolded prior to assembly and flat, mark and cut out the top and bottom panel openings leaving a 2” margin of board all around the perimeter.
- Fold and assemble box after hollytex panels are in place.
Panel opening with hollytex
- Using Heritage board (the same board as the box construction material) cut a matching window mat to fit on the inside of the lid and box bottom that matches the panel opening on the box lid and bottom.
- Stretch a piece of hollytex taut to the underside of the window mat (grey side) with small pieces of archival double-sided tape.
- Apply the adhesive (Jade PVA 403 mixed with MC) to the underside of the mat. Turn the mat over and position on the inside of the box lid making sure the panel openings are aligned. Weight until dry. Repeat process for bottom panel.
- Fold and assemble box. [Figure 7].
Padded and raised support-lifts
- Design the custom template for the shape of the support-lift based on 1) the contour of the puppet configuration swiveled to fit the box dimension, 2) planning for bumper block locations to reduce puppet movement, and 3) allowing for space to grab the lift for removal from the box. [Figure 8]
- Using the template as a guide, cut the support-lift from Heritage board with an Olfa knife or other cutting knife. Note that straight line cuts provide cleaner and tidier cuts than curved shapes.
- Secure volara (1/4” thick) to the support-lift with low melt adhesive. Either cut the volara to the exact contour of the lift prior to gluing or trim excess volara after gluing. Volara provides a barrier between the calcium buffered board which may chemically interact with the cellulose nitrate when in contact. Volara also provides a soft cushion for the brittle film.
- Raise the support-lift up to allow for ease of removal by gluing a secondary board of acid-free corrugated board, similar in contour but smaller and recessed, underneath the lift. The raised support-lift also reduces the chance that the plastic film will come in contact with the buffered board of the box construction. Adhesive options include Jade 403 or low melt adhesive. [Figure 9] Volara provides a barrier between the buffered board and archival box which may chemically interact with the cellulose nitrate when in contact. Volara also provides a soft cushion for the brittle film. Note the lift is raised from the base of the tray by the use of a smaller and recessed secondary board
Construct a removable tray from the Heritage board the same dimension of the box. The tray serves several functions:
- provides the platform to support the lift,
- is cut away, as much as possible, to allow for airflow yet is structurally sound, and
- has space allocated for the bumpers to be attached which reduce puppet movement. [Figure 10]
- Bumpers are constructed of 1/8” volara wrapped around and glued to ethafoam blocks with low melt adhesive. Use a light touch on the adhesive application to avoid excess glue and heat. Having pre-cut strips of volara the height of the bumper and trimming the excess length of the strip after gluing works well.
- The shape and placement of the bumpers are custom to each puppet. The goal is to use as few bumpers as necessary and place them strategically to limit potential movement of the puppet during transport. Bumper height is the height of the box interior (less a small amount to account for the mat and tray thickness.)
- Secure the bumpers to the tray with low melt adhesive.
- Secure blocks of ethafoam to the four corners of the tray to provide additional support for the box for stacking.
- Use low melt adhesive to glue the blocks to the tray.
- Secure blocks of ethafoam to the four exterior corners of the box bottom to provide space between boxes for airflow when stacked.
- Use low melt adhesive to glue the blocks to the box bottom. [Figure 11]
Store at low temperatures, away from light, with ventilation to aid in the removal of off-gasses. Do not place in closed cabinets. If the storage area is not dark, a cover or another solid box (with spacer feet) can be placed on the top of the stack to reduce exposure to light and dust.
Use of scavengers was considered but not utilized due to insufficient research into their use with cellulose nitrate. Of concern was the hazard of use without routine replacement. (Shashoua)
Literature regarding the storage materials for nitrate film negatives and those for objects made with cellulose nitrate are not in full agreement on the issue of contact with paper.
Personal communications with Pamela Hatchfield (Objects Conservator, Boston MFA), Bruno Pouliot (Objects Conservator, Winterthur Museum), Mary Coughlin (George Washington University), Doug Nishimura (Scientist, Image Permanence Institute), and John Mayer (Museum Curator and Collection Storage Specialist) regarding design and on chemically acceptable materials to be in contact with cellulose nitrate objects.
Hatchfield, Pamela. Pollutants in the Museum Environment. Archetype Publications. 2002 (pages 132-133, 92-94)
Shashoua, Yvonne. Storage Strategies for Plastics. Conservation Perspectives- The GCI Newsletter. Spring 2014
Quyle, Anita and Colin Williamson, editors. Plastics: Collection and Conserving. 1999
Plastic film, off-gassing, mixed media, passive airflow